Technically speaking, the use of infrared sensing pits is not necessarily 'seeing', as in using 'sight'. But it does make a great deal of sense that species which strike out at birds would use either better than average eyesight, or infrared pits, to locate their prey. That ETB/GTP convergent evolution is definitely quite amazing...
As I understand it (and I'm quite willing to be corrected!) snake vision does vary a lot between species, but generally they have fewer cone cells than rod cells, compared to humans. Since cones in humans are the colour sensing cells, it is assumed that snakes do see colour, but not as well as we do.
I'm not aware of any detailed studies of snake vision- perhaps someone with easy access to a university library could have a look (how about it, Ryan?). However, my old animal physiology text does mention that rod cells sense colour in some vertebrates, and specifically mentions frogs.